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                                <h1 id="&#x7F16;&#x7A0B;&#x98CE;&#x683C;">&#x7F16;&#x7A0B;&#x98CE;&#x683C;</h1>
<h2 id="&#x6982;&#x8FF0;">&#x6982;&#x8FF0;</h2>
<p>&#x201C;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#x201D;&#xFF08;programming style&#xFF09;&#x6307;&#x7684;&#x662F;&#x7F16;&#x5199;&#x4EE3;&#x7801;&#x7684;&#x6837;&#x5F0F;&#x89C4;&#x5219;&#x3002;&#x4E0D;&#x540C;&#x7684;&#x7A0B;&#x5E8F;&#x5458;&#xFF0C;&#x5F80;&#x5F80;&#x6709;&#x4E0D;&#x540C;&#x7684;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#x3002;</p>
<p>&#x6709;&#x4EBA;&#x8BF4;&#xFF0C;&#x7F16;&#x8BD1;&#x5668;&#x7684;&#x89C4;&#x8303;&#x53EB;&#x505A;&#x201C;&#x8BED;&#x6CD5;&#x89C4;&#x5219;&#x201D;&#xFF08;grammar&#xFF09;&#xFF0C;&#x8FD9;&#x662F;&#x7A0B;&#x5E8F;&#x5458;&#x5FC5;&#x987B;&#x9075;&#x5B88;&#x7684;&#xFF1B;&#x800C;&#x7F16;&#x8BD1;&#x5668;&#x5FFD;&#x7565;&#x7684;&#x90E8;&#x5206;&#xFF0C;&#x5C31;&#x53EB;&#x201C;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#x201D;&#xFF08;programming style&#xFF09;&#xFF0C;&#x8FD9;&#x662F;&#x7A0B;&#x5E8F;&#x5458;&#x53EF;&#x4EE5;&#x81EA;&#x7531;&#x9009;&#x62E9;&#x7684;&#x3002;&#x8FD9;&#x79CD;&#x8BF4;&#x6CD5;&#x4E0D;&#x5B8C;&#x5168;&#x6B63;&#x786E;&#xFF0C;&#x7A0B;&#x5E8F;&#x5458;&#x56FA;&#x7136;&#x53EF;&#x4EE5;&#x81EA;&#x7531;&#x9009;&#x62E9;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#xFF0C;&#x4F46;&#x662F;&#x597D;&#x7684;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#x6709;&#x52A9;&#x4E8E;&#x5199;&#x51FA;&#x8D28;&#x91CF;&#x66F4;&#x9AD8;&#x3001;&#x9519;&#x8BEF;&#x66F4;&#x5C11;&#x3001;&#x66F4;&#x6613;&#x4E8E;&#x7EF4;&#x62A4;&#x7684;&#x7A0B;&#x5E8F;&#x3002;</p>
<p>&#x6240;&#x4EE5;&#xFF0C;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#x7684;&#x9009;&#x62E9;&#x4E0D;&#x5E94;&#x8BE5;&#x57FA;&#x4E8E;&#x4E2A;&#x4EBA;&#x7231;&#x597D;&#x3001;&#x719F;&#x6089;&#x7A0B;&#x5EA6;&#x3001;&#x6253;&#x5B57;&#x91CF;&#x7B49;&#x56E0;&#x7D20;&#xFF0C;&#x800C;&#x8981;&#x8003;&#x8651;&#x5982;&#x4F55;&#x5C3D;&#x91CF;&#x4F7F;&#x4EE3;&#x7801;&#x6E05;&#x6670;&#x6613;&#x8BFB;&#x3001;&#x51CF;&#x5C11;&#x51FA;&#x9519;&#x3002;&#x4F60;&#x9009;&#x62E9;&#x7684;&#xFF0C;&#x4E0D;&#x662F;&#x4F60;&#x559C;&#x6B22;&#x7684;&#x98CE;&#x683C;&#xFF0C;&#x800C;&#x662F;&#x4E00;&#x79CD;&#x80FD;&#x591F;&#x6E05;&#x6670;&#x8868;&#x8FBE;&#x4F60;&#x7684;&#x610F;&#x56FE;&#x7684;&#x98CE;&#x683C;&#x3002;&#x8FD9;&#x4E00;&#x70B9;&#xFF0C;&#x5BF9;&#x4E8E; JavaScript &#x8FD9;&#x79CD;&#x8BED;&#x6CD5;&#x81EA;&#x7531;&#x5EA6;&#x5F88;&#x9AD8;&#x7684;&#x8BED;&#x8A00;&#x5C24;&#x5176;&#x91CD;&#x8981;&#x3002;</p>
<p>&#x5FC5;&#x987B;&#x7262;&#x8BB0;&#x7684;&#x4E00;&#x70B9;&#x662F;&#xFF0C;&#x5982;&#x679C;&#x4F60;&#x9009;&#x5B9A;&#x4E86;&#x4E00;&#x79CD;&#x201C;&#x7F16;&#x7A0B;&#x98CE;&#x683C;&#x201D;&#xFF0C;&#x5C31;&#x5E94;&#x8BE5;&#x575A;&#x6301;&#x9075;&#x5B88;&#xFF0C;&#x5207;&#x5FCC;&#x591A;&#x79CD;&#x98CE;&#x683C;&#x6DF7;&#x7528;&#x3002;&#x5982;&#x679C;&#x4F60;&#x52A0;&#x5165;&#x4ED6;&#x4EBA;&#x7684;&#x9879;&#x76EE;&#xFF0C;&#x5C31;&#x5E94;&#x8BE5;&#x9075;&#x5B88;&#x73B0;&#x6709;&#x7684;&#x98CE;&#x683C;&#x3002;</p>
<h2 id="&#x7F29;&#x8FDB;">&#x7F29;&#x8FDB;</h2>
<p>&#x884C;&#x9996;&#x7684;&#x7A7A;&#x683C;&#x548C; Tab &#x952E;&#xFF0C;&#x90FD;&#x53EF;&#x4EE5;&#x4EA7;&#x751F;&#x4EE3;&#x7801;&#x7F29;&#x8FDB;&#x6548;&#x679C;&#xFF08;indent&#xFF09;&#x3002;</p>
<p>Tab &#x952E;&#x53EF;&#x4EE5;&#x8282;&#x7701;&#x51FB;&#x952E;&#x6B21;&#x6570;&#xFF0C;&#x4F46;&#x4E0D;&#x540C;&#x7684;&#x6587;&#x672C;&#x7F16;&#x8F91;&#x5668;&#x5BF9; Tab &#x7684;&#x663E;&#x793A;&#x4E0D;&#x5C3D;&#x76F8;&#x540C;&#xFF0C;&#x6709;&#x7684;&#x663E;&#x793A;&#x56DB;&#x4E2A;&#x7A7A;&#x683C;&#xFF0C;&#x6709;&#x7684;&#x663E;&#x793A;&#x4E24;&#x4E2A;&#x7A7A;&#x683C;&#xFF0C;&#x6240;&#x4EE5;&#x6709;&#x4EBA;&#x89C9;&#x5F97;&#xFF0C;&#x7A7A;&#x683C;&#x952E;&#x53EF;&#x4EE5;&#x4F7F;&#x5F97;&#x663E;&#x793A;&#x6548;&#x679C;&#x66F4;&#x7EDF;&#x4E00;&#x3002;</p>
<p>&#x65E0;&#x8BBA;&#x4F60;&#x9009;&#x62E9;&#x54EA;&#x4E00;&#x79CD;&#x65B9;&#x6CD5;&#xFF0C;&#x90FD;&#x662F;&#x53EF;&#x4EE5;&#x63A5;&#x53D7;&#x7684;&#xFF0C;&#x8981;&#x505A;&#x7684;&#x5C31;&#x662F;&#x59CB;&#x7EC8;&#x575A;&#x6301;&#x8FD9;&#x4E00;&#x79CD;&#x9009;&#x62E9;&#x3002;&#x4E0D;&#x8981;&#x4E00;&#x4F1A;&#x4F7F;&#x7528; Tab &#x952E;&#xFF0C;&#x4E00;&#x4F1A;&#x4F7F;&#x7528;&#x7A7A;&#x683C;&#x952E;&#x3002;</p>
<h2 id="&#x533A;&#x5757;">&#x533A;&#x5757;</h2>
<p>&#x5982;&#x679C;&#x5FAA;&#x73AF;&#x548C;&#x5224;&#x65AD;&#x7684;&#x4EE3;&#x7801;&#x4F53;&#x53EA;&#x6709;&#x4E00;&#x884C;&#xFF0C;JavaScript &#x5141;&#x8BB8;&#x8BE5;&#x533A;&#x5757;&#xFF08;block&#xFF09;&#x7701;&#x7565;&#x5927;&#x62EC;&#x53F7;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (a)
  b();
  c();
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x7684;&#x539F;&#x610F;&#x53EF;&#x80FD;&#x662F;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (a) {
  b();
  c();
}
</code></pre>
<p>&#x4F46;&#x662F;&#xFF0C;&#x5B9E;&#x9645;&#x6548;&#x679C;&#x5374;&#x662F;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (a) {
  b();
}
  c();
</code></pre>
<p>&#x56E0;&#x6B64;&#xFF0C;&#x5EFA;&#x8BAE;&#x603B;&#x662F;&#x4F7F;&#x7528;&#x5927;&#x62EC;&#x53F7;&#x8868;&#x793A;&#x533A;&#x5757;&#x3002;</p>
<p>&#x53E6;&#x5916;&#xFF0C;&#x533A;&#x5757;&#x8D77;&#x9996;&#x7684;&#x5927;&#x62EC;&#x53F7;&#x7684;&#x4F4D;&#x7F6E;&#xFF0C;&#x6709;&#x8BB8;&#x591A;&#x4E0D;&#x540C;&#x7684;&#x5199;&#x6CD5;&#x3002;&#x6700;&#x6D41;&#x884C;&#x7684;&#x6709;&#x4E24;&#x79CD;&#xFF0C;&#x4E00;&#x79CD;&#x662F;&#x8D77;&#x9996;&#x7684;&#x5927;&#x62EC;&#x53F7;&#x53E6;&#x8D77;&#x4E00;&#x884C;&#x3002;</p>
<pre><code class="lang-javascript">block
{
  <span class="hljs-comment">// ...</span>
}
</code></pre>
<p>&#x53E6;&#x4E00;&#x79CD;&#x662F;&#x8D77;&#x9996;&#x7684;&#x5927;&#x62EC;&#x53F7;&#x8DDF;&#x5728;&#x5173;&#x952E;&#x5B57;&#x7684;&#x540E;&#x9762;&#x3002;</p>
<pre><code class="lang-javascript">block {
  <span class="hljs-comment">// ...</span>
}
</code></pre>
<p>&#x4E00;&#x822C;&#x6765;&#x8BF4;&#xFF0C;&#x8FD9;&#x4E24;&#x79CD;&#x5199;&#x6CD5;&#x90FD;&#x53EF;&#x4EE5;&#x63A5;&#x53D7;&#x3002;&#x4F46;&#x662F;&#xFF0C;JavaScript &#x8981;&#x4F7F;&#x7528;&#x540E;&#x4E00;&#x79CD;&#xFF0C;&#x56E0;&#x4E3A; JavaScript &#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x53E5;&#x672B;&#x7684;&#x5206;&#x53F7;&#xFF0C;&#x5BFC;&#x81F4;&#x4E00;&#x4E9B;&#x96BE;&#x4EE5;&#x5BDF;&#x89C9;&#x7684;&#x9519;&#x8BEF;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">return</span>
{
  key: value
};

<span class="hljs-comment">// &#x76F8;&#x5F53;&#x4E8E;</span>
<span class="hljs-keyword">return</span>;
{
  key: value
};
</code></pre>
<p>&#x4E0A;&#x9762;&#x7684;&#x4EE3;&#x7801;&#x7684;&#x539F;&#x610F;&#xFF0C;&#x662F;&#x8981;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x5BF9;&#x8C61;&#xFF0C;&#x4F46;&#x5B9E;&#x9645;&#x4E0A;&#x8FD4;&#x56DE;&#x7684;&#x662F;<code>undefined</code>&#xFF0C;&#x56E0;&#x4E3A; JavaScript &#x81EA;&#x52A8;&#x5728;<code>return</code>&#x8BED;&#x53E5;&#x540E;&#x9762;&#x6DFB;&#x52A0;&#x4E86;&#x5206;&#x53F7;&#x3002;&#x4E3A;&#x4E86;&#x907F;&#x514D;&#x8FD9;&#x4E00;&#x7C7B;&#x9519;&#x8BEF;&#xFF0C;&#x9700;&#x8981;&#x5199;&#x6210;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">return</span> {
  key : value
};
</code></pre>
<p>&#x56E0;&#x6B64;&#xFF0C;&#x8868;&#x793A;&#x533A;&#x5757;&#x8D77;&#x9996;&#x7684;&#x5927;&#x62EC;&#x53F7;&#xFF0C;&#x4E0D;&#x8981;&#x53E6;&#x8D77;&#x4E00;&#x884C;&#x3002;</p>
<h2 id="&#x5706;&#x62EC;&#x53F7;">&#x5706;&#x62EC;&#x53F7;</h2>
<p>&#x5706;&#x62EC;&#x53F7;&#xFF08;parentheses&#xFF09;&#x5728; JavaScript &#x4E2D;&#x6709;&#x4E24;&#x79CD;&#x4F5C;&#x7528;&#xFF0C;&#x4E00;&#x79CD;&#x8868;&#x793A;&#x51FD;&#x6570;&#x7684;&#x8C03;&#x7528;&#xFF0C;&#x53E6;&#x4E00;&#x79CD;&#x8868;&#x793A;&#x8868;&#x8FBE;&#x5F0F;&#x7684;&#x7EC4;&#x5408;&#xFF08;grouping&#xFF09;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// &#x5706;&#x62EC;&#x53F7;&#x8868;&#x793A;&#x51FD;&#x6570;&#x7684;&#x8C03;&#x7528;</span>
<span class="hljs-built_in">console</span>.log(<span class="hljs-string">&apos;abc&apos;</span>);

<span class="hljs-comment">// &#x5706;&#x62EC;&#x53F7;&#x8868;&#x793A;&#x8868;&#x8FBE;&#x5F0F;&#x7684;&#x7EC4;&#x5408;</span>
(<span class="hljs-number">1</span> + <span class="hljs-number">2</span>) * <span class="hljs-number">3</span>
</code></pre>
<p>&#x5EFA;&#x8BAE;&#x53EF;&#x4EE5;&#x7528;&#x7A7A;&#x683C;&#xFF0C;&#x533A;&#x5206;&#x8FD9;&#x4E24;&#x79CD;&#x4E0D;&#x540C;&#x7684;&#x62EC;&#x53F7;&#x3002;</p>
<blockquote>
<ol>
<li><p>&#x8868;&#x793A;&#x51FD;&#x6570;&#x8C03;&#x7528;&#x65F6;&#xFF0C;&#x51FD;&#x6570;&#x540D;&#x4E0E;&#x5DE6;&#x62EC;&#x53F7;&#x4E4B;&#x95F4;&#x6CA1;&#x6709;&#x7A7A;&#x683C;&#x3002;</p>
</li>
<li><p>&#x8868;&#x793A;&#x51FD;&#x6570;&#x5B9A;&#x4E49;&#x65F6;&#xFF0C;&#x51FD;&#x6570;&#x540D;&#x4E0E;&#x5DE6;&#x62EC;&#x53F7;&#x4E4B;&#x95F4;&#x6CA1;&#x6709;&#x7A7A;&#x683C;&#x3002;</p>
</li>
<li><p>&#x5176;&#x4ED6;&#x60C5;&#x51B5;&#x65F6;&#xFF0C;&#x524D;&#x9762;&#x4F4D;&#x7F6E;&#x7684;&#x8BED;&#x6CD5;&#x5143;&#x7D20;&#x4E0E;&#x5DE6;&#x62EC;&#x53F7;&#x4E4B;&#x95F4;&#xFF0C;&#x90FD;&#x6709;&#x4E00;&#x4E2A;&#x7A7A;&#x683C;&#x3002;</p>
</li>
</ol>
</blockquote>
<p>&#x6309;&#x7167;&#x4E0A;&#x9762;&#x7684;&#x89C4;&#x5219;&#xFF0C;&#x4E0B;&#x9762;&#x7684;&#x5199;&#x6CD5;&#x90FD;&#x662F;&#x4E0D;&#x89C4;&#x8303;&#x7684;&#x3002;</p>
<pre><code class="lang-javascript">foo (bar)
<span class="hljs-keyword">return</span>(a+b);
<span class="hljs-keyword">if</span>(a === <span class="hljs-number">0</span>) {...}
<span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">foo</span> (<span class="hljs-params">b</span>) </span>{...}
<span class="hljs-function"><span class="hljs-keyword">function</span>(<span class="hljs-params">x</span>) </span>{...}
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x7684;&#x6700;&#x540E;&#x4E00;&#x884C;&#x662F;&#x4E00;&#x4E2A;&#x533F;&#x540D;&#x51FD;&#x6570;&#xFF0C;<code>function</code>&#x662F;&#x8BED;&#x6CD5;&#x5173;&#x952E;&#x5B57;&#xFF0C;&#x4E0D;&#x662F;&#x51FD;&#x6570;&#x540D;&#xFF0C;&#x6240;&#x4EE5;&#x4E0E;&#x5DE6;&#x62EC;&#x53F7;&#x4E4B;&#x95F4;&#x5E94;&#x8BE5;&#x8981;&#x6709;&#x4E00;&#x4E2A;&#x7A7A;&#x683C;&#x3002;</p>
<h2 id="&#x884C;&#x5C3E;&#x7684;&#x5206;&#x53F7;">&#x884C;&#x5C3E;&#x7684;&#x5206;&#x53F7;</h2>
<p>&#x5206;&#x53F7;&#x8868;&#x793A;&#x4E00;&#x6761;&#x8BED;&#x53E5;&#x7684;&#x7ED3;&#x675F;&#x3002;JavaScript &#x5141;&#x8BB8;&#x7701;&#x7565;&#x884C;&#x5C3E;&#x7684;&#x5206;&#x53F7;&#x3002;&#x4E8B;&#x5B9E;&#x4E0A;&#xFF0C;&#x786E;&#x5B9E;&#x6709;&#x4E00;&#x4E9B;&#x5F00;&#x53D1;&#x8005;&#x884C;&#x5C3E;&#x4ECE;&#x6765;&#x4E0D;&#x5199;&#x5206;&#x53F7;&#x3002;&#x4F46;&#x662F;&#xFF0C;&#x7531;&#x4E8E;&#x4E0B;&#x9762;&#x8981;&#x8BA8;&#x8BBA;&#x7684;&#x539F;&#x56E0;&#xFF0C;&#x5EFA;&#x8BAE;&#x8FD8;&#x662F;&#x4E0D;&#x8981;&#x7701;&#x7565;&#x8FD9;&#x4E2A;&#x5206;&#x53F7;&#x3002;</p>
<h3 id="&#x4E0D;&#x4F7F;&#x7528;&#x5206;&#x53F7;&#x7684;&#x60C5;&#x51B5;">&#x4E0D;&#x4F7F;&#x7528;&#x5206;&#x53F7;&#x7684;&#x60C5;&#x51B5;</h3>
<p>&#x9996;&#x5148;&#xFF0C;&#x4EE5;&#x4E0B;&#x4E09;&#x79CD;&#x60C5;&#x51B5;&#xFF0C;&#x8BED;&#x6CD5;&#x89C4;&#x5B9A;&#x672C;&#x6765;&#x5C31;&#x4E0D;&#x9700;&#x8981;&#x5728;&#x7ED3;&#x5C3E;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x3002;</p>
<p><strong>&#xFF08;1&#xFF09;for &#x548C; while &#x5FAA;&#x73AF;</strong></p>
<pre><code class="lang-javascript"><span class="hljs-keyword">for</span> ( ; ; ) {
} <span class="hljs-comment">// &#x6CA1;&#x6709;&#x5206;&#x53F7;</span>

<span class="hljs-keyword">while</span> (<span class="hljs-literal">true</span>) {
} <span class="hljs-comment">// &#x6CA1;&#x6709;&#x5206;&#x53F7;</span>
</code></pre>
<p>&#x6CE8;&#x610F;&#xFF0C;<code>do...while</code>&#x5FAA;&#x73AF;&#x662F;&#x6709;&#x5206;&#x53F7;&#x7684;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">do</span> {
  a--;
} <span class="hljs-keyword">while</span>(a &gt; <span class="hljs-number">0</span>); <span class="hljs-comment">// &#x5206;&#x53F7;&#x4E0D;&#x80FD;&#x7701;&#x7565;</span>
</code></pre>
<p><strong>&#xFF08;2&#xFF09;&#x5206;&#x652F;&#x8BED;&#x53E5;&#xFF1A;if&#xFF0C;switch&#xFF0C;try</strong></p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (<span class="hljs-literal">true</span>) {
} <span class="hljs-comment">// &#x6CA1;&#x6709;&#x5206;&#x53F7;</span>

<span class="hljs-keyword">switch</span> () {
} <span class="hljs-comment">// &#x6CA1;&#x6709;&#x5206;&#x53F7;</span>

<span class="hljs-keyword">try</span> {
} <span class="hljs-keyword">catch</span> {
} <span class="hljs-comment">// &#x6CA1;&#x6709;&#x5206;&#x53F7;</span>
</code></pre>
<p><strong>&#xFF08;3&#xFF09;&#x51FD;&#x6570;&#x7684;&#x58F0;&#x660E;&#x8BED;&#x53E5;</strong></p>
<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">f</span>(<span class="hljs-params"></span>) </span>{
} <span class="hljs-comment">// &#x6CA1;&#x6709;&#x5206;&#x53F7;</span>
</code></pre>
<p>&#x6CE8;&#x610F;&#xFF0C;&#x51FD;&#x6570;&#x8868;&#x8FBE;&#x5F0F;&#x4ECD;&#x7136;&#x8981;&#x4F7F;&#x7528;&#x5206;&#x53F7;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">var</span> f = <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">f</span>(<span class="hljs-params"></span>) </span>{
};
</code></pre>
<p>&#x4EE5;&#x4E0A;&#x4E09;&#x79CD;&#x60C5;&#x51B5;&#xFF0C;&#x5982;&#x679C;&#x4F7F;&#x7528;&#x4E86;&#x5206;&#x53F7;&#xFF0C;&#x5E76;&#x4E0D;&#x4F1A;&#x51FA;&#x9519;&#x3002;&#x56E0;&#x4E3A;&#xFF0C;&#x89E3;&#x91CA;&#x5F15;&#x64CE;&#x4F1A;&#x628A;&#x8FD9;&#x4E2A;&#x5206;&#x53F7;&#x89E3;&#x91CA;&#x4E3A;&#x7A7A;&#x8BED;&#x53E5;&#x3002;</p>
<h3 id="&#x5206;&#x53F7;&#x7684;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;">&#x5206;&#x53F7;&#x7684;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;</h3>
<p>&#x9664;&#x4E86;&#x4E0A;&#x4E00;&#x8282;&#x7684;&#x4E09;&#x79CD;&#x60C5;&#x51B5;&#xFF0C;&#x6240;&#x6709;&#x8BED;&#x53E5;&#x90FD;&#x5E94;&#x8BE5;&#x4F7F;&#x7528;&#x5206;&#x53F7;&#x3002;&#x4F46;&#x662F;&#xFF0C;&#x5982;&#x679C;&#x6CA1;&#x6709;&#x4F7F;&#x7528;&#x5206;&#x53F7;&#xFF0C;&#x5927;&#x591A;&#x6570;&#x60C5;&#x51B5;&#x4E0B;&#xFF0C;JavaScript &#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">var</span> a = <span class="hljs-number">1</span>
<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E;</span>
<span class="hljs-keyword">var</span> a = <span class="hljs-number">1</span>;
</code></pre>
<p>&#x8FD9;&#x79CD;&#x8BED;&#x6CD5;&#x7279;&#x6027;&#x88AB;&#x79F0;&#x4E3A;&#x201C;&#x5206;&#x53F7;&#x7684;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x201D;&#xFF08;Automatic Semicolon Insertion&#xFF0C;&#x7B80;&#x79F0; ASI&#xFF09;&#x3002;</p>
<p>&#x56E0;&#x6B64;&#xFF0C;&#x6709;&#x4EBA;&#x63D0;&#x5021;&#x7701;&#x7565;&#x53E5;&#x5C3E;&#x7684;&#x5206;&#x53F7;&#x3002;&#x9EBB;&#x70E6;&#x7684;&#x662F;&#xFF0C;&#x5982;&#x679C;&#x4E0B;&#x4E00;&#x884C;&#x7684;&#x5F00;&#x59CB;&#x53EF;&#x4EE5;&#x4E0E;&#x672C;&#x884C;&#x7684;&#x7ED3;&#x5C3E;&#x8FDE;&#x5728;&#x4E00;&#x8D77;&#x89E3;&#x91CA;&#xFF0C;JavaScript &#x5C31;&#x4E0D;&#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E; var a = 3</span>
<span class="hljs-keyword">var</span>
a
=
<span class="hljs-number">3</span>

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E; &apos;abc&apos;.length</span>
<span class="hljs-string">&apos;abc&apos;</span>
.length

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E; return a + b;</span>
<span class="hljs-keyword">return</span> a +
b;

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E; obj.foo(arg1, arg2);</span>
obj.foo(arg1,
arg2);

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E; 3 * 2 + 10 * (27 / 6)</span>
<span class="hljs-number">3</span> * <span class="hljs-number">2</span>
+
<span class="hljs-number">10</span> * (<span class="hljs-number">27</span> / <span class="hljs-number">6</span>)
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x90FD;&#x4F1A;&#x591A;&#x884C;&#x653E;&#x5728;&#x4E00;&#x8D77;&#x89E3;&#x91CA;&#xFF0C;&#x4E0D;&#x4F1A;&#x6BCF;&#x4E00;&#x884C;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x3002;&#x8FD9;&#x4E9B;&#x4F8B;&#x5B50;&#x8FD8;&#x662F;&#x6BD4;&#x8F83;&#x5BB9;&#x6613;&#x770B;&#x51FA;&#x6765;&#x7684;&#xFF0C;&#x4F46;&#x662F;&#x4E0B;&#x9762;&#x8FD9;&#x4E2A;&#x4F8B;&#x5B50;&#x5C31;&#x4E0D;&#x90A3;&#x4E48;&#x5BB9;&#x6613;&#x770B;&#x51FA;&#x6765;&#x4E86;&#x3002;</p>
<pre><code class="lang-javascript">x = y
(<span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
  <span class="hljs-comment">// ...</span>
})();

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E;</span>
x = y(<span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{...})();
</code></pre>
<p>&#x4E0B;&#x9762;&#x662F;&#x66F4;&#x591A;&#x4E0D;&#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x7684;&#x4F8B;&#x5B50;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-comment">// &#x5F15;&#x64CE;&#x89E3;&#x91CA;&#x4E3A; c(d+e)</span>
<span class="hljs-keyword">var</span> a = b + c
(d+e).toString();

<span class="hljs-comment">// &#x5F15;&#x64CE;&#x89E3;&#x91CA;&#x4E3A; a = b/hi/g.exec(c).map(d)</span>
<span class="hljs-comment">// &#x6B63;&#x5219;&#x8868;&#x8FBE;&#x5F0F;&#x7684;&#x659C;&#x6760;&#xFF0C;&#x4F1A;&#x5F53;&#x4F5C;&#x9664;&#x6CD5;&#x8FD0;&#x7B97;&#x7B26;</span>
a = b
/hi/g.exec(c).map(d);

<span class="hljs-comment">// &#x89E3;&#x91CA;&#x4E3A;&apos;b&apos;[&apos;red&apos;, &apos;green&apos;]&#xFF0C;</span>
<span class="hljs-comment">// &#x5373;&#x628A;&#x5B57;&#x7B26;&#x4E32;&#x5F53;&#x4F5C;&#x4E00;&#x4E2A;&#x6570;&#x7EC4;&#xFF0C;&#x6309;&#x7D22;&#x5F15;&#x53D6;&#x503C;</span>
<span class="hljs-keyword">var</span> a = <span class="hljs-string">&apos;b&apos;</span>
[<span class="hljs-string">&apos;red&apos;</span>, <span class="hljs-string">&apos;green&apos;</span>].forEach(<span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">c</span>) </span>{
  <span class="hljs-built_in">console</span>.log(c);
})

<span class="hljs-comment">// &#x89E3;&#x91CA;&#x4E3A; function (x) { return x }(a++)</span>
<span class="hljs-comment">// &#x5373;&#x8C03;&#x7528;&#x533F;&#x540D;&#x51FD;&#x6570;&#xFF0C;&#x7ED3;&#x679C;f&#x7B49;&#x4E8E;0</span>
<span class="hljs-keyword">var</span> a = <span class="hljs-number">0</span>;
<span class="hljs-keyword">var</span> f = <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params">x</span>) </span>{ <span class="hljs-keyword">return</span> x }
(a++)
</code></pre>
<p>&#x53EA;&#x6709;&#x4E0B;&#x4E00;&#x884C;&#x7684;&#x5F00;&#x59CB;&#x4E0E;&#x672C;&#x884C;&#x7684;&#x7ED3;&#x5C3E;&#xFF0C;&#x65E0;&#x6CD5;&#x653E;&#x5728;&#x4E00;&#x8D77;&#x89E3;&#x91CA;&#xFF0C;JavaScript &#x5F15;&#x64CE;&#x624D;&#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (a &lt; <span class="hljs-number">0</span>) a = <span class="hljs-number">0</span>
<span class="hljs-built_in">console</span>.log(a)

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E;&#x4E0B;&#x9762;&#x7684;&#x4EE3;&#x7801;&#xFF0C;</span>
<span class="hljs-comment">// &#x56E0;&#x4E3A; 0console &#x6CA1;&#x6709;&#x610F;&#x4E49;</span>
<span class="hljs-keyword">if</span> (a &lt; <span class="hljs-number">0</span>) a = <span class="hljs-number">0</span>;
<span class="hljs-built_in">console</span>.log(a)
</code></pre>
<p>&#x53E6;&#x5916;&#xFF0C;&#x5982;&#x679C;&#x4E00;&#x884C;&#x7684;&#x8D77;&#x9996;&#x662F;&#x201C;&#x81EA;&#x589E;&#x201D;&#xFF08;<code>++</code>&#xFF09;&#x6216;&#x201C;&#x81EA;&#x51CF;&#x201D;&#xFF08;<code>--</code>&#xFF09;&#x8FD0;&#x7B97;&#x7B26;&#xFF0C;&#x5219;&#x5B83;&#x4EEC;&#x7684;&#x524D;&#x9762;&#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x3002;</p>
<pre><code class="lang-javascript">a = b = c = <span class="hljs-number">1</span>

a
++
b
--
c

<span class="hljs-built_in">console</span>.log(a, b, c)
<span class="hljs-comment">// 1 2 0</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x4EE3;&#x7801;&#x4E4B;&#x6240;&#x4EE5;&#x4F1A;&#x5F97;&#x5230;<code>1 2 0</code>&#x7684;&#x7ED3;&#x679C;&#xFF0C;&#x539F;&#x56E0;&#x662F;&#x81EA;&#x589E;&#x548C;&#x81EA;&#x51CF;&#x8FD0;&#x7B97;&#x7B26;&#x524D;&#xFF0C;&#x81EA;&#x52A8;&#x52A0;&#x4E0A;&#x4E86;&#x5206;&#x53F7;&#x3002;&#x4E0A;&#x9762;&#x7684;&#x4EE3;&#x7801;&#x5B9E;&#x9645;&#x4E0A;&#x7B49;&#x540C;&#x4E8E;&#x4E0B;&#x9762;&#x7684;&#x5F62;&#x5F0F;&#x3002;</p>
<pre><code class="lang-javascript">a = b = c = <span class="hljs-number">1</span>;
a;
++b;
--c;
</code></pre>
<p>&#x5982;&#x679C;<code>continue</code>&#x3001;<code>break</code>&#x3001;<code>return</code>&#x548C;<code>throw</code>&#x8FD9;&#x56DB;&#x4E2A;&#x8BED;&#x53E5;&#x540E;&#x9762;&#xFF0C;&#x76F4;&#x63A5;&#x8DDF;&#x6362;&#x884C;&#x7B26;&#xFF0C;&#x5219;&#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x3002;&#x8FD9;&#x610F;&#x5473;&#x7740;&#xFF0C;&#x5982;&#x679C;<code>return</code>&#x8BED;&#x53E5;&#x8FD4;&#x56DE;&#x7684;&#x662F;&#x4E00;&#x4E2A;&#x5BF9;&#x8C61;&#x7684;&#x5B57;&#x9762;&#x91CF;&#xFF0C;&#x8D77;&#x9996;&#x7684;&#x5927;&#x62EC;&#x53F7;&#x4E00;&#x5B9A;&#x8981;&#x5199;&#x5728;&#x540C;&#x4E00;&#x884C;&#xFF0C;&#x5426;&#x5219;&#x5F97;&#x4E0D;&#x5230;&#x9884;&#x671F;&#x7ED3;&#x679C;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">return</span>
{ first: <span class="hljs-string">&apos;Jane&apos;</span> };

<span class="hljs-comment">// &#x89E3;&#x91CA;&#x6210;</span>
<span class="hljs-keyword">return</span>;
{ first: <span class="hljs-string">&apos;Jane&apos;</span> };
</code></pre>
<p>&#x7531;&#x4E8E;&#x89E3;&#x91CA;&#x5F15;&#x64CE;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#x7684;&#x884C;&#x4E3A;&#x96BE;&#x4EE5;&#x9884;&#x6D4B;&#xFF0C;&#x56E0;&#x6B64;&#x7F16;&#x5199;&#x4EE3;&#x7801;&#x7684;&#x65F6;&#x5019;&#x4E0D;&#x5E94;&#x8BE5;&#x7701;&#x7565;&#x884C;&#x5C3E;&#x7684;&#x5206;&#x53F7;&#x3002;</p>
<p>&#x4E0D;&#x5E94;&#x8BE5;&#x7701;&#x7565;&#x7ED3;&#x5C3E;&#x7684;&#x5206;&#x53F7;&#xFF0C;&#x8FD8;&#x6709;&#x4E00;&#x4E2A;&#x539F;&#x56E0;&#x3002;&#x6709;&#x4E9B; JavaScript &#x4EE3;&#x7801;&#x538B;&#x7F29;&#x5668;&#xFF08;uglifier&#xFF09;&#x4E0D;&#x4F1A;&#x81EA;&#x52A8;&#x6DFB;&#x52A0;&#x5206;&#x53F7;&#xFF0C;&#x56E0;&#x6B64;&#x9047;&#x5230;&#x6CA1;&#x6709;&#x5206;&#x53F7;&#x7684;&#x7ED3;&#x5C3E;&#xFF0C;&#x5C31;&#x4F1A;&#x8BA9;&#x4EE3;&#x7801;&#x4FDD;&#x6301;&#x539F;&#x72B6;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x538B;&#x7F29;&#x6210;&#x4E00;&#x884C;&#xFF0C;&#x4F7F;&#x5F97;&#x538B;&#x7F29;&#x65E0;&#x6CD5;&#x5F97;&#x5230;&#x6700;&#x4F18;&#x7684;&#x7ED3;&#x679C;&#x3002;</p>
<p>&#x53E6;&#x5916;&#xFF0C;&#x4E0D;&#x5199;&#x7ED3;&#x5C3E;&#x7684;&#x5206;&#x53F7;&#xFF0C;&#x53EF;&#x80FD;&#x4F1A;&#x5BFC;&#x81F4;&#x811A;&#x672C;&#x5408;&#x5E76;&#x51FA;&#x9519;&#x3002;&#x6240;&#x4EE5;&#xFF0C;&#x6709;&#x7684;&#x4EE3;&#x7801;&#x5E93;&#x5728;&#x7B2C;&#x4E00;&#x884C;&#x8BED;&#x53E5;&#x5F00;&#x59CB;&#x524D;&#xFF0C;&#x4F1A;&#x52A0;&#x4E0A;&#x4E00;&#x4E2A;&#x5206;&#x53F7;&#x3002;</p>
<pre><code class="lang-javascript">;<span class="hljs-keyword">var</span> a = <span class="hljs-number">1</span>;
<span class="hljs-comment">// ...</span>
</code></pre>
<p>&#x4E0A;&#x9762;&#x8FD9;&#x79CD;&#x5199;&#x6CD5;&#x5C31;&#x53EF;&#x4EE5;&#x907F;&#x514D;&#x4E0E;&#x5176;&#x4ED6;&#x811A;&#x672C;&#x5408;&#x5E76;&#x65F6;&#xFF0C;&#x6392;&#x5728;&#x524D;&#x9762;&#x7684;&#x811A;&#x672C;&#x6700;&#x540E;&#x4E00;&#x884C;&#x8BED;&#x53E5;&#x6CA1;&#x6709;&#x5206;&#x53F7;&#xFF0C;&#x5BFC;&#x81F4;&#x8FD0;&#x884C;&#x51FA;&#x9519;&#x7684;&#x95EE;&#x9898;&#x3002;</p>
<h2 id="&#x5168;&#x5C40;&#x53D8;&#x91CF;">&#x5168;&#x5C40;&#x53D8;&#x91CF;</h2>
<p>JavaScript &#x6700;&#x5927;&#x7684;&#x8BED;&#x6CD5;&#x7F3A;&#x70B9;&#xFF0C;&#x53EF;&#x80FD;&#x5C31;&#x662F;&#x5168;&#x5C40;&#x53D8;&#x91CF;&#x5BF9;&#x4E8E;&#x4EFB;&#x4F55;&#x4E00;&#x4E2A;&#x4EE3;&#x7801;&#x5757;&#xFF0C;&#x90FD;&#x662F;&#x53EF;&#x8BFB;&#x53EF;&#x5199;&#x3002;&#x8FD9;&#x5BF9;&#x4EE3;&#x7801;&#x7684;&#x6A21;&#x5757;&#x5316;&#x548C;&#x91CD;&#x590D;&#x4F7F;&#x7528;&#xFF0C;&#x975E;&#x5E38;&#x4E0D;&#x5229;&#x3002;</p>
<p>&#x56E0;&#x6B64;&#xFF0C;&#x5EFA;&#x8BAE;&#x907F;&#x514D;&#x4F7F;&#x7528;&#x5168;&#x5C40;&#x53D8;&#x91CF;&#x3002;&#x5982;&#x679C;&#x4E0D;&#x5F97;&#x4E0D;&#x4F7F;&#x7528;&#xFF0C;&#x53EF;&#x4EE5;&#x8003;&#x8651;&#x7528;&#x5927;&#x5199;&#x5B57;&#x6BCD;&#x8868;&#x793A;&#x53D8;&#x91CF;&#x540D;&#xFF0C;&#x8FD9;&#x6837;&#x66F4;&#x5BB9;&#x6613;&#x770B;&#x51FA;&#x8FD9;&#x662F;&#x5168;&#x5C40;&#x53D8;&#x91CF;&#xFF0C;&#x6BD4;&#x5982;<code>UPPER_CASE</code>&#x3002;</p>
<h2 id="&#x53D8;&#x91CF;&#x58F0;&#x660E;">&#x53D8;&#x91CF;&#x58F0;&#x660E;</h2>
<p>JavaScript &#x4F1A;&#x81EA;&#x52A8;&#x5C06;&#x53D8;&#x91CF;&#x58F0;&#x660E;&#x201C;&#x63D0;&#x5347;&#x201D;&#xFF08;hoist&#xFF09;&#x5230;&#x4EE3;&#x7801;&#x5757;&#xFF08;block&#xFF09;&#x7684;&#x5934;&#x90E8;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (!x) {
  <span class="hljs-keyword">var</span> x = {};
}

<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E;</span>
<span class="hljs-keyword">var</span> x;
<span class="hljs-keyword">if</span> (!x) {
  x = {};
}
</code></pre>
<p>&#x8FD9;&#x610F;&#x5473;&#x7740;&#xFF0C;&#x53D8;&#x91CF;<code>x</code>&#x662F;<code>if</code>&#x4EE3;&#x7801;&#x5757;&#x4E4B;&#x524D;&#x5C31;&#x5B58;&#x5728;&#x4E86;&#x3002;&#x4E3A;&#x4E86;&#x907F;&#x514D;&#x53EF;&#x80FD;&#x51FA;&#x73B0;&#x7684;&#x95EE;&#x9898;&#xFF0C;&#x6700;&#x597D;&#x628A;&#x53D8;&#x91CF;&#x58F0;&#x660E;&#x90FD;&#x653E;&#x5728;&#x4EE3;&#x7801;&#x5757;&#x7684;&#x5934;&#x90E8;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">for</span> (<span class="hljs-keyword">var</span> i = <span class="hljs-number">0</span>; i &lt; <span class="hljs-number">10</span>; i++) {
  <span class="hljs-comment">// ...</span>
}

<span class="hljs-comment">// &#x5199;&#x6210;</span>
<span class="hljs-keyword">var</span> i;
<span class="hljs-keyword">for</span> (i = <span class="hljs-number">0</span>; i &lt; <span class="hljs-number">10</span>; i++) {
  <span class="hljs-comment">// ...</span>
}
</code></pre>
<p>&#x4E0A;&#x9762;&#x8FD9;&#x6837;&#x7684;&#x5199;&#x6CD5;&#xFF0C;&#x5C31;&#x5BB9;&#x6613;&#x770B;&#x51FA;&#x5B58;&#x5728;&#x4E00;&#x4E2A;&#x5168;&#x5C40;&#x7684;&#x5FAA;&#x73AF;&#x53D8;&#x91CF;<code>i</code>&#x3002;</p>
<p>&#x53E6;&#x5916;&#xFF0C;&#x6240;&#x6709;&#x51FD;&#x6570;&#x90FD;&#x5E94;&#x8BE5;&#x5728;&#x4F7F;&#x7528;&#x4E4B;&#x524D;&#x5B9A;&#x4E49;&#x3002;&#x51FD;&#x6570;&#x5185;&#x90E8;&#x7684;&#x53D8;&#x91CF;&#x58F0;&#x660E;&#xFF0C;&#x90FD;&#x5E94;&#x8BE5;&#x653E;&#x5728;&#x51FD;&#x6570;&#x7684;&#x5934;&#x90E8;&#x3002;</p>
<h2 id="with-&#x8BED;&#x53E5;">with &#x8BED;&#x53E5;</h2>
<p><code>with</code>&#x53EF;&#x4EE5;&#x51CF;&#x5C11;&#x4EE3;&#x7801;&#x7684;&#x4E66;&#x5199;&#xFF0C;&#x4F46;&#x662F;&#x4F1A;&#x9020;&#x6210;&#x6DF7;&#x6DC6;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">with</span> (o) {
&#x3000;foo = bar;
}
</code></pre>
<p>&#x4E0A;&#x9762;&#x7684;&#x4EE3;&#x7801;&#xFF0C;&#x53EF;&#x4EE5;&#x6709;&#x56DB;&#x79CD;&#x8FD0;&#x884C;&#x7ED3;&#x679C;&#xFF1A;</p>
<pre><code class="lang-javascript">o.foo = bar;
o.foo = o.bar;
foo = bar;
foo = o.bar;
</code></pre>
<p>&#x8FD9;&#x56DB;&#x79CD;&#x7ED3;&#x679C;&#x90FD;&#x53EF;&#x80FD;&#x53D1;&#x751F;&#xFF0C;&#x53D6;&#x51B3;&#x4E8E;&#x4E0D;&#x540C;&#x7684;&#x53D8;&#x91CF;&#x662F;&#x5426;&#x6709;&#x5B9A;&#x4E49;&#x3002;&#x56E0;&#x6B64;&#xFF0C;&#x4E0D;&#x8981;&#x4F7F;&#x7528;<code>with</code>&#x8BED;&#x53E5;&#x3002;</p>
<h2 id="&#x76F8;&#x7B49;&#x548C;&#x4E25;&#x683C;&#x76F8;&#x7B49;">&#x76F8;&#x7B49;&#x548C;&#x4E25;&#x683C;&#x76F8;&#x7B49;</h2>
<p>JavaScript &#x6709;&#x4E24;&#x4E2A;&#x8868;&#x793A;&#x76F8;&#x7B49;&#x7684;&#x8FD0;&#x7B97;&#x7B26;&#xFF1A;&#x201C;&#x76F8;&#x7B49;&#x201D;&#xFF08;<code>==</code>&#xFF09;&#x548C;&#x201C;&#x4E25;&#x683C;&#x76F8;&#x7B49;&#x201D;&#xFF08;<code>===</code>&#xFF09;&#x3002;</p>
<p>&#x76F8;&#x7B49;&#x8FD0;&#x7B97;&#x7B26;&#x4F1A;&#x81EA;&#x52A8;&#x8F6C;&#x6362;&#x53D8;&#x91CF;&#x7C7B;&#x578B;&#xFF0C;&#x9020;&#x6210;&#x5F88;&#x591A;&#x610F;&#x60F3;&#x4E0D;&#x5230;&#x7684;&#x60C5;&#x51B5;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-number">0</span> == <span class="hljs-string">&apos;&apos;</span><span class="hljs-comment">// true</span>
<span class="hljs-number">1</span> == <span class="hljs-literal">true</span> <span class="hljs-comment">// true</span>
<span class="hljs-number">2</span> == <span class="hljs-literal">true</span> <span class="hljs-comment">// false</span>
<span class="hljs-number">0</span> == <span class="hljs-string">&apos;0&apos;</span> <span class="hljs-comment">// true</span>
<span class="hljs-literal">false</span> == <span class="hljs-string">&apos;false&apos;</span> <span class="hljs-comment">// false</span>
<span class="hljs-literal">false</span> == <span class="hljs-string">&apos;0&apos;</span> <span class="hljs-comment">// true</span>
<span class="hljs-string">&apos; \t\r\n &apos;</span> == <span class="hljs-number">0</span> <span class="hljs-comment">// true</span>
</code></pre>
<p>&#x56E0;&#x6B64;&#xFF0C;&#x5EFA;&#x8BAE;&#x4E0D;&#x8981;&#x4F7F;&#x7528;&#x76F8;&#x7B49;&#x8FD0;&#x7B97;&#x7B26;&#xFF08;<code>==</code>&#xFF09;&#xFF0C;&#x53EA;&#x4F7F;&#x7528;&#x4E25;&#x683C;&#x76F8;&#x7B49;&#x8FD0;&#x7B97;&#x7B26;&#xFF08;<code>===</code>&#xFF09;&#x3002;</p>
<h2 id="&#x8BED;&#x53E5;&#x7684;&#x5408;&#x5E76;">&#x8BED;&#x53E5;&#x7684;&#x5408;&#x5E76;</h2>
<p>&#x6709;&#x4E9B;&#x7A0B;&#x5E8F;&#x5458;&#x8FFD;&#x6C42;&#x7B80;&#x6D01;&#xFF0C;&#x559C;&#x6B22;&#x5408;&#x5E76;&#x4E0D;&#x540C;&#x76EE;&#x7684;&#x7684;&#x8BED;&#x53E5;&#x3002;&#x6BD4;&#x5982;&#xFF0C;&#x539F;&#x6765;&#x7684;&#x8BED;&#x53E5;&#x662F;</p>
<pre><code class="lang-javascript">a = b;
<span class="hljs-keyword">if</span> (a) {
  <span class="hljs-comment">// ...</span>
}
</code></pre>
<p>&#x4ED6;&#x559C;&#x6B22;&#x5199;&#x6210;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> (a = b) {
  <span class="hljs-comment">// ...</span>
}
</code></pre>
<p>&#x867D;&#x7136;&#x8BED;&#x53E5;&#x5C11;&#x4E86;&#x4E00;&#x884C;&#xFF0C;&#x4F46;&#x662F;&#x53EF;&#x8BFB;&#x6027;&#x5927;&#x6253;&#x6298;&#x6263;&#xFF0C;&#x800C;&#x4E14;&#x4F1A;&#x9020;&#x6210;&#x8BEF;&#x8BFB;&#xFF0C;&#x8BA9;&#x522B;&#x4EBA;&#x8BEF;&#x89E3;&#x8FD9;&#x884C;&#x4EE3;&#x7801;&#x7684;&#x610F;&#x601D;&#x662F;&#x4E0B;&#x9762;&#x8FD9;&#x6837;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">if</span> &#xFF08;a === b&#xFF09;{
  <span class="hljs-comment">// ...</span>
}
</code></pre>
<p>&#x5EFA;&#x8BAE;&#x4E0D;&#x8981;&#x5C06;&#x4E0D;&#x540C;&#x76EE;&#x7684;&#x7684;&#x8BED;&#x53E5;&#xFF0C;&#x5408;&#x5E76;&#x6210;&#x4E00;&#x884C;&#x3002;</p>
<h2 id="&#x81EA;&#x589E;&#x548C;&#x81EA;&#x51CF;&#x8FD0;&#x7B97;&#x7B26;">&#x81EA;&#x589E;&#x548C;&#x81EA;&#x51CF;&#x8FD0;&#x7B97;&#x7B26;</h2>
<p>&#x81EA;&#x589E;&#xFF08;<code>++</code>&#xFF09;&#x548C;&#x81EA;&#x51CF;&#xFF08;<code>--</code>&#xFF09;&#x8FD0;&#x7B97;&#x7B26;&#xFF0C;&#x653E;&#x5728;&#x53D8;&#x91CF;&#x7684;&#x524D;&#x9762;&#x6216;&#x540E;&#x9762;&#xFF0C;&#x8FD4;&#x56DE;&#x7684;&#x503C;&#x4E0D;&#x4E00;&#x6837;&#xFF0C;&#x5F88;&#x5BB9;&#x6613;&#x53D1;&#x751F;&#x9519;&#x8BEF;&#x3002;&#x4E8B;&#x5B9E;&#x4E0A;&#xFF0C;&#x6240;&#x6709;&#x7684;<code>++</code>&#x8FD0;&#x7B97;&#x7B26;&#x90FD;&#x53EF;&#x4EE5;&#x7528;<code>+= 1</code>&#x4EE3;&#x66FF;&#x3002;</p>
<pre><code class="lang-javascript">++x
<span class="hljs-comment">// &#x7B49;&#x540C;&#x4E8E;</span>
x += <span class="hljs-number">1</span>;
</code></pre>
<p>&#x6539;&#x7528;<code>+= 1</code>&#xFF0C;&#x4EE3;&#x7801;&#x53D8;&#x5F97;&#x66F4;&#x6E05;&#x6670;&#x4E86;&#x3002;</p>
<p>&#x5EFA;&#x8BAE;&#x81EA;&#x589E;&#xFF08;<code>++</code>&#xFF09;&#x548C;&#x81EA;&#x51CF;&#xFF08;<code>--</code>&#xFF09;&#x8FD0;&#x7B97;&#x7B26;&#x5C3D;&#x91CF;&#x4F7F;&#x7528;<code>+=</code>&#x548C;<code>-=</code>&#x4EE3;&#x66FF;&#x3002;</p>
<h2 id="switchcase-&#x7ED3;&#x6784;">switch...case &#x7ED3;&#x6784;</h2>
<p><code>switch...case</code>&#x7ED3;&#x6784;&#x8981;&#x6C42;&#xFF0C;&#x5728;&#x6BCF;&#x4E00;&#x4E2A;<code>case</code>&#x7684;&#x6700;&#x540E;&#x4E00;&#x884C;&#x5FC5;&#x987B;&#x662F;<code>break</code>&#x8BED;&#x53E5;&#xFF0C;&#x5426;&#x5219;&#x4F1A;&#x63A5;&#x7740;&#x8FD0;&#x884C;&#x4E0B;&#x4E00;&#x4E2A;<code>case</code>&#x3002;&#x8FD9;&#x6837;&#x4E0D;&#x4EC5;&#x5BB9;&#x6613;&#x5FD8;&#x8BB0;&#xFF0C;&#x8FD8;&#x4F1A;&#x9020;&#x6210;&#x4EE3;&#x7801;&#x7684;&#x5197;&#x957F;&#x3002;</p>
<p>&#x800C;&#x4E14;&#xFF0C;<code>switch...case</code>&#x4E0D;&#x4F7F;&#x7528;&#x5927;&#x62EC;&#x53F7;&#xFF0C;&#x4E0D;&#x5229;&#x4E8E;&#x4EE3;&#x7801;&#x5F62;&#x5F0F;&#x7684;&#x7EDF;&#x4E00;&#x3002;&#x6B64;&#x5916;&#xFF0C;&#x8FD9;&#x79CD;&#x7ED3;&#x6784;&#x7C7B;&#x4F3C;&#x4E8E;<code>goto</code>&#x8BED;&#x53E5;&#xFF0C;&#x5BB9;&#x6613;&#x9020;&#x6210;&#x7A0B;&#x5E8F;&#x6D41;&#x7A0B;&#x7684;&#x6DF7;&#x4E71;&#xFF0C;&#x4F7F;&#x5F97;&#x4EE3;&#x7801;&#x7ED3;&#x6784;&#x6DF7;&#x4E71;&#x4E0D;&#x582A;&#xFF0C;&#x4E0D;&#x7B26;&#x5408;&#x9762;&#x5411;&#x5BF9;&#x8C61;&#x7F16;&#x7A0B;&#x7684;&#x539F;&#x5219;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">doAction</span>(<span class="hljs-params">action</span>) </span>{
  <span class="hljs-keyword">switch</span> (action) {
    <span class="hljs-keyword">case</span> <span class="hljs-string">&apos;hack&apos;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&apos;hack&apos;</span>;
    <span class="hljs-keyword">case</span> <span class="hljs-string">&apos;slash&apos;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&apos;slash&apos;</span>;
    <span class="hljs-keyword">case</span> <span class="hljs-string">&apos;run&apos;</span>:
      <span class="hljs-keyword">return</span> <span class="hljs-string">&apos;run&apos;</span>;
    <span class="hljs-keyword">default</span>:
      <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-built_in">Error</span>(<span class="hljs-string">&apos;Invalid action.&apos;</span>);
  }
}
</code></pre>
<p>&#x4E0A;&#x9762;&#x7684;&#x4EE3;&#x7801;&#x5EFA;&#x8BAE;&#x6539;&#x5199;&#x6210;&#x5BF9;&#x8C61;&#x7ED3;&#x6784;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">doAction</span>(<span class="hljs-params">action</span>) </span>{
  <span class="hljs-keyword">var</span> actions = {
    <span class="hljs-string">&apos;hack&apos;</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">return</span> <span class="hljs-string">&apos;hack&apos;</span>;
    },
    <span class="hljs-string">&apos;slash&apos;</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">return</span> <span class="hljs-string">&apos;slash&apos;</span>;
    },
    <span class="hljs-string">&apos;run&apos;</span>: <span class="hljs-function"><span class="hljs-keyword">function</span> (<span class="hljs-params"></span>) </span>{
      <span class="hljs-keyword">return</span> <span class="hljs-string">&apos;run&apos;</span>;
    }
  };

  <span class="hljs-keyword">if</span> (<span class="hljs-keyword">typeof</span> actions[action] !== <span class="hljs-string">&apos;function&apos;</span>) {
    <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-built_in">Error</span>(<span class="hljs-string">&apos;Invalid action.&apos;</span>);
  }

  <span class="hljs-keyword">return</span> actions[action]();
}
</code></pre>
<p>&#x56E0;&#x6B64;&#xFF0C;&#x5EFA;&#x8BAE;<code>switch...case</code>&#x7ED3;&#x6784;&#x53EF;&#x4EE5;&#x7528;&#x5BF9;&#x8C61;&#x7ED3;&#x6784;&#x4EE3;&#x66FF;&#x3002;</p>
<h2 id="&#x53C2;&#x8003;&#x94FE;&#x63A5;">&#x53C2;&#x8003;&#x94FE;&#x63A5;</h2>
<ul>
<li>Eric Elliott, Programming JavaScript Applications, <a href="http://chimera.labs.oreilly.com/books/1234000000262/ch02.html" target="_blank" rel="nofollow">Chapter 2. JavaScript Style Guide</a>, O&apos;Reilly, 2013</li>
<li>Axel Rauschmayer, <a href="http://www.2ality.com/2013/07/meta-style-guide.html" target="_blank" rel="nofollow">A meta style guide for JavaScript</a></li>
<li>Axel Rauschmayer, <a href="http://www.2ality.com/2011/05/semicolon-insertion.html" target="_blank" rel="nofollow">Automatic semicolon insertion in JavaScript</a></li>
<li>Rod Vagg, <a href="http://dailyjs.com/2012/04/19/semicolons/" target="_blank" rel="nofollow">JavaScript and Semicolons</a></li>
</ul>




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